<div id="wrapper">
	<textarea id="editor1" cols="10" rows="10">
		<p>Foo bar.</p>
		<p>Foo bar.</p>
	</textarea>
</div>
<button id="btn">Toggle</button>

<script>
	CKEDITOR.replace( 'editor1' );

	var isHidden = false;
	document.getElementById( 'btn' ).onclick = function() {
		var style = isHidden ? 'block' : 'none';
		document.getElementById( 'wrapper' ).style.display = style;
		isHidden = !isHidden;
	};
</script>
